Article Abstract Background: We studied the patterns and predictors of long-acting injectable (LAI) antipsychotic (AP) use in the treatment of schizophrenia and the effect of introducing a new LAI (paliperidone palmitate ) in the Spanish province of Tarragona. Methods: This noninterventional, naturalistic, retrospective study included electronic medical record data from a large population-based database of 1,646 patients who were diagnosed with schizophrenia according to ICD-10 criteria and treated between January 2011 and December 2013. Results: During the study period, 42.0% of patients were treated with an LAI AP. The most frequently prescribed initial LAI was risperidone (52.0% of patients). A total of 23% of patients initially treated with an oral AP were switched to an LAI AP, a change that was associated with younger age (P = .001), undifferentiated schizophrenia (P = .015), substance abuse (P < .001), and neuropsychiatric comedication with the following agents: anticonvulsants (P = .004), anticholinergics (P < .001), and hypnotics/sedatives (P = .03). The change from an oral AP to paliperidone-LAI was predicted by younger age (P < .001). Overall, 27.5% of patients switched to another LAI AP, and paliperidone-LAI was the preferred option in 64.7% of cases. The most frequent change involved patients taking risperidone-LAI, many of whom transitioned to paliperidone-LAI (85.0% of cases), particularly patients with a disease duration > 5 years (P = .019). Conclusions: There was a progressive increase in the use of LAI formulations in our catchment area. These agents were preferentially prescribed to patients with chronic disease and a history of substance abuse, as well as patients receiving neuropsychiatric comedication. One-month LAI formulations were commonly used in young patients.